"Naming and shaming" employers who don't pay the living wage is likely to have disappointing results.

Ed Miliband is campaigning for companies to pay the living wage, currently £7.45 an hour. Photograph: Getty Images.

Labour says it would "name and shame[3]" employers that don’t pay all their workers a living wage – the income a person needs to be able to afford a basic standard of living. But how shaming would inclusion on Miliband's list of offenders be? Employers on it wouldn’t exactly stand out: KPMG calculates that one in five[4] UK workers are not paid a living wage, which stands at £7.45, or £8.55 in London.

That makes for safety in numbers, and with low wages heavily concentrated in certain sectors – 70 per cent of cleaners, waiters, and kitchen staff are paid less than the recommended rate – the competitors of affected companies would be even less likely to pay the wage, keeping the pressure to change low.

Miliband’s pledge recalls the strategy of anti-tax-avoidance protest group UK Uncut, which drew attention to high profile companies that avoided large sums of tax, in the hope of shaming them into paying more. The campaign succeeded in raising the issue up the political agenda – but corporate tax avoidance is still rife, and there have so far been no major public reversals by their targets: at the height of the protests last year, companies like Vodafone[5] reported record profits, whilst spokespeople simply repeat that they are following the law.

One aim of UK Uncut was to urge politicians to act on the issue and change the law, but as a politician himself, Miliband’s approach to low pay seems somewhat confused. Low paid workers may well also ask why Labour needs to be in government to do what a small campaign group did with a Twitter account and a lot of time on their hands.

UK Uncut also had the advantage of focusing its fire on specific, high profile offenders. But if a Labour government were to target specific companies to get high-profile results, they'd be likely to fall foul of EU state aid regulations: governments are strictly forbidden[6] from picking on certain companies, or offering an "advantage in any form whatsoever conferred on a selective basis to undertakings by national public authorities".

The "name and shame" approach could even be embarrassing for Labour, which doesn’t have a spotless record on the living wage itself. Relying on negative media coverage and civil society to do the job could end up with the party turning its fire on itself. The party’s longest serving living Prime Minister only recently signed up[7] to paying his staff the bare minimum wage, and Tony Blair, among others, would be one of those shamed for not paying the living rate if the proposals were comprehensively implemented.

If Labour is serious about workers earning a living wage then it will probably find the results of its flirtation with business voluntarism disappointing. The actions of companies are ultimately guided by the profit motive and shareholder value, and recent history suggests that activism can rarely, by itself, create corporate social responsibility out of thin air.